[Enhancement #73] Working on modifications of second level cache to s…

…upport plural contexts.

jopa-impl/src/main/java/cz/cvut/kbss/jopa/sessions/RepositoryMap.java

@@ -1,31 +1,28 @@
 /**
  * Copyright (C) 2020 Czech Technical University in Prague
- *
- * This program is free software: you can redistribute it and/or modify it under
- * the terms of the GNU General Public License as published by the Free Software
- * Foundation, either version 3 of the License, or (at your option) any
- * later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
- * details. You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ * <p>
+ * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ * <p>
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details. You should have received a copy of the GNU General Public License along with this program. If not, see
+ * <http://www.gnu.org/licenses/>.
  */
 package cz.cvut.kbss.jopa.sessions;
 
+import cz.cvut.kbss.jopa.model.descriptors.Descriptor;
+
 import java.net.URI;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.Map;
-
-import cz.cvut.kbss.jopa.model.descriptors.Descriptor;
+import java.util.Set;
 
 final class RepositoryMap {
 
-    private static final URI DEFAULT_CONTEXT = URI.create("http://defaultContext");
-
-    private final Map<URI, Map<Object, Object>> origsToClones = new HashMap<>();
+    private final Map<Set<URI>, Map<Object, Object>> origsToClones = new HashMap<>();
     private Map<Object, Descriptor> entityDescriptors;
 
     RepositoryMap() {
@@ -91,13 +88,11 @@ Descriptor getEntityDescriptor(Object entity) {
 
     void clear() {
         origsToClones.values().forEach(Map::clear);
-        if (entityDescriptors != null) {
-            initDescriptors();
-        }
+        initDescriptors();
     }
 
     private Map<Object, Object> getMap(Descriptor descriptor) {
-        final URI ctx = descriptor.getContext() != null ? descriptor.getContext() : DEFAULT_CONTEXT;
+        final Set<URI> ctx = descriptor.getContexts();
         Map<Object, Object> entities;
         if (!origsToClones.containsKey(ctx)) {
             entities = new IdentityHashMap<>();

jopa-impl/src/main/java/cz/cvut/kbss/jopa/sessions/UnitOfWorkImpl.java

@@ -562,7 +562,7 @@ private void mergeChangesIntoParent() {
     private void evictPossiblyUpdatedReferencesFromCache() {
         cloneToOriginals.forEach((clone, orig) -> {
             if (orig == null && !deletedObjects.containsKey(clone)) {
-                removeObjectFromCache(clone, getDescriptor(clone).getContext());
+                removeObjectFromCache(clone, getDescriptor(clone).getSingleContext().orElse(null));
             }
         });
     }
@@ -618,7 +618,7 @@ private <T> T mergeDetachedInternal(T entity, Descriptor descriptor) {
             throw e;
         }
         if (cacheManager.contains(et.getJavaType(), idUri, descriptor)) {
-            cacheManager.evict(et.getJavaType(), idUri, descriptor.getContext());
+            cacheManager.evict(et.getJavaType(), idUri, descriptor.getSingleContext().orElse(null));
         }
         setHasChanges();
         checkForIndirectObjects(clone);

jopa-impl/src/main/java/cz/cvut/kbss/jopa/sessions/cache/EntityCache.java

@@ -17,10 +17,7 @@
 import cz.cvut.kbss.jopa.model.descriptors.Descriptor;
 
 import java.net.URI;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.IdentityHashMap;
-import java.util.Map;
+import java.util.*;
 
 class EntityCache {
 
@@ -41,9 +38,12 @@ class EntityCache {
     void put(Object identifier, Object entity, Descriptor descriptor) {
         assert identifier != null;
         assert entity != null;
+        if (!isCacheable(descriptor)) {
+            return;
+        }
 
         final Class<?> cls = entity.getClass();
-        final URI ctx = descriptor.getContext() != null ? descriptor.getContext() : defaultContext;
+        final URI ctx = descriptor.getSingleContext().orElse(defaultContext);
 
         Map<Object, Map<Class<?>, Object>> ctxMap;
         if (!repoCache.containsKey(ctx)) {
@@ -66,12 +66,15 @@ void put(Object identifier, Object entity, Descriptor descriptor) {
         descriptors.put(entity, descriptor);
     }
 
+    boolean isCacheable(Descriptor descriptor) {
+        return descriptor.getContexts().size() <= 1;
+    }
+
     <T> T get(Class<T> cls, Object identifier, Descriptor descriptor) {
         assert cls != null;
         assert identifier != null;
 
-        final URI ctx = descriptor.getContext() != null ? descriptor.getContext() : defaultContext;
-        final Map<Class<?>, Object> m = getMapForId(ctx, identifier);
+        final Map<Class<?>, Object> m = getMapForId(descriptor.getContexts(), identifier);
         final Object result = m.get(cls);
 
         return result != null && descriptors.get(result).equals(descriptor) ? cls.cast(result) : null;
@@ -82,14 +85,20 @@ boolean contains(Class<?> cls, Object identifier, Descriptor descriptor) {
         assert identifier != null;
         assert descriptor != null;
 
-        final Map<Class<?>, Object> m = getMapForId(descriptor.getContext(), identifier);
-        if (!m.containsKey(cls)) {
-            return false;
+        final Set<URI> contexts = descriptor.getContexts().isEmpty() ? Collections.singleton(defaultContext) : descriptor.getContexts();
+        for (URI ctx : contexts) {
+            final Map<Class<?>, Object> m = getMapForId(ctx, identifier);
+            if (!m.containsKey(cls)) {
+                continue;
+            }
+            final Object result = m.get(cls);
+            assert descriptors.containsKey(result);
+
+            if (descriptors.get(result).equals(descriptor)) {
+                return true;
+            }
         }
-        final Object result = m.get(cls);
-        assert descriptors.containsKey(result);
-
-        return descriptors.get(result).equals(descriptor);
+        return false;
     }
 
     void evict(Class<?> cls, Object identifier, URI context) {

jopa-impl/src/main/java/cz/cvut/kbss/jopa/sessions/cache/LruCacheManager.java

@@ -1,16 +1,14 @@
 /**
  * Copyright (C) 2020 Czech Technical University in Prague
- *
- * This program is free software: you can redistribute it and/or modify it under
- * the terms of the GNU General Public License as published by the Free Software
- * Foundation, either version 3 of the License, or (at your option) any
- * later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
- * details. You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ * <p>
+ * This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ * <p>
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details. You should have received a copy of the GNU General Public License along with this program. If not, see
+ * <http://www.gnu.org/licenses/>.
  */
 package cz.cvut.kbss.jopa.sessions.cache;
 
@@ -215,7 +213,10 @@ public void accept(LruCache.CacheNode cacheNode) {
 
         @Override
         void put(Object identifier, Object entity, Descriptor descriptor) {
-            final URI ctx = descriptor.getContext() != null ? descriptor.getContext() : defaultContext;
+            if (!isCacheable(descriptor)) {
+                return;
+            }
+            final URI ctx = descriptor.getSingleContext().orElse(defaultContext);
             super.put(identifier, entity, descriptor);
             cache.put(new LruCache.CacheNode(ctx, entity.getClass(), identifier), NULL_VALUE);
         }

jopa-impl/src/main/java/cz/cvut/kbss/jopa/sessions/cache/TtlCacheManager.java

@@ -285,7 +285,7 @@ public void run() {
                 final List<URI> toEvict = new ArrayList<>();
                 // Mark the objects for eviction (can't evict them now, it would
                 // cause ConcurrentModificationException)
-                for (Entry<URI, Long> e : cache.ttls.entrySet()) {
+                for (Entry<URI, Long> e : cache.ttl.entrySet()) {
                     final long lm = e.getValue();
                     if (lm + TtlCacheManager.this.timeToLive < currentTime) {
                         toEvict.add(e.getKey());
@@ -302,12 +302,15 @@ public void run() {
 
     private static final class TtlCache extends EntityCache {
 
-        private final Map<URI, Long> ttls = new HashMap<>();
+        private final Map<URI, Long> ttl = new HashMap<>();
 
         @Override
         void put(Object identifier, Object entity, Descriptor descriptor) {
+            if (!isCacheable(descriptor)) {
+                return;
+            }
             super.put(identifier, entity, descriptor);
-            final URI ctx = descriptor.getContext() != null ? descriptor.getContext() : defaultContext;
+            final URI ctx = descriptor.getSingleContext().orElse(defaultContext);
             updateTimeToLive(ctx);
         }
 
@@ -327,14 +330,14 @@ <T> T get(Class<T> cls, Object identifier, Descriptor descriptor) {
         private void updateTimeToLive(URI context) {
             assert context != null;
 
-            ttls.put(context, System.currentTimeMillis());
+            ttl.put(context, System.currentTimeMillis());
         }
 
         @Override
         void evict(URI context) {
             final URI ctx = context != null ? context : defaultContext;
             super.evict(ctx);
-            ttls.remove(context);
+            ttl.remove(context);
         }
 
         @Override
@@ -348,7 +351,7 @@ void evict(Class<?> cls) {
                     }
                 }
                 if (m.isEmpty()) {
-                    ttls.remove(e.getKey());
+                    ttl.remove(e.getKey());
                 }
             }
         }